You are sitting in the middle of a row and the windows are too small for you to see much outside. There is a clatter of safety belts as your fellow passengers settle in their seats. Then, a muffled bang at the front of the cabin tells you the doors are being closed, and the plane draws slowly away from the terminal. It rumbles along the taxiway, wings flapping gently as it rides over the bumps. A flight attendant mimes the safety procedures while another bustles down the aisle checking the lockers and seat belts. Finally the plane halts at the end of the runway. People stop talking.

Suddenly there is a roaring noise, followed by a surge of power as the pilot releases the brakes. The plane gathers speed, clinging to the ground for what seems like an age, then the cabin tilts, and surreally, the airport and the surrounding countryside drop away. From the moment of take-off, the aircraft takes around 15 minutes to reaching cruising altitude, where the engine noise lessens, the cabin levels off, and there’s a stir as the passengers relax and unfasten their belts. Up here, the ride seems smooth and effortless. But outside, the temperature is 50 degrees Celsius below zero and the air too thin for humans to survive.

There are said to be around a million passengers in the sky at any given time. They are flying because they can: jet airliners have shrunk the dimensions of international travel to the point where a journey across the world seems hardly more memorable than a Sunday outing in the family car. A large organisation with trained staff and a great deal of equipment both in the air and on the ground are needed to make this happen. In this web site, we’ll concentrate on the technology, how machines can be made to perform reliably under extreme conditions. The challenges are severe, the most obvious being that a flying machine moves up and down as well as across the landscape, and negotiating this extra dimension places more responsibility on the engineers who design and build the machine together with pilot who flies it. There are few options if anything goes wrong during a flight. When a car breaks down, it stops by the side of the road, while a ship can be towed to the nearest port. But an aircraft has to descend under its own resources, and without engine power and a fully functioning control system, a safe landing may not be possible.

In reality, accidents involving aircraft are very rare, but the consequences are severe, and this raises the stakes for all concerned. The industry strives to improve safety but the cost of each successive improvement rises. This is because as the accident numbers fall, the threats become less tangible, often hard to imagine if they haven’t occurred before. Consequently, the aeronautical engineer must work at the leading edge of science and mathematics to predict how an aircraft will behave. And when a problem is recognised and the designer works out a solution, how is the solution to be tested? You can expose a car to all sorts of mechanical failure on a test track and even wreck it to see what happens. You can’t do that with a jumbo jet. In this web site, we’ll concentrate mostly on the relationship between the machine and its surroundings, and in particular the air flow that keeps it aloft.